The present disclosure relates to a selectable one-way clutch.
As a one-way clutch, U.S. Pat. No. 6,571,926 discloses a selectable one-way clutch including a pocket plate including a plurality of pockets in which struts are accommodated, a notch plate including a plurality of notches to be engaged with the struts, and a selector plate arranged between the pocket plate and the notch plate, and which switches an engaged state and a non-engaged state.
Here, in the above-described selectable one-way clutch, while the notch plate is rotated at a high speed in an engaging direction (positive direction) with respect to the pocket plate, the selector plate may be erroneously rotated for some reason and the struts may be erroneously engaged with the notches in the notch plate rotated at a high speed.
Therefore, to protect components from a shock due to the erroneous engagement, a conventional selectable one-way clutch is provided with a function to suppress the erroneous engagement by flipping the strut by a portion other than the notches in the notch plate (hereinafter, the function is referred to as “ratchet function”) when the notch plate is rotated in the engaging direction by the fixed number of revolutions or more.
However, in a conventional selectable one-way clutch 101, as illustrated by a portion A in FIG. 10, an upper surface 13a of a strut 13 may stick to a plane portion 122 between notches 121 adjacent along a peripheral direction due to surface tension of oil (illustration is omitted) lying between a notch plate 120 and the strut 13, when the notch plate 120 flips the strut 13 (hereinafter, referred to as “at the time of ratchet”).
As a result, as illustrated by the arrow B in FIG. 10, the strut 13 is drawn into the notch 121 with the rotation of the notch plate 120 and may be erroneously engaged with the notch 121. Note that, in FIG. 10, a plurality of contours of the strut 13 in motion is superimposed in order to illustrate change of the posture of the strut 13 at the time of ratchet in time series in order from the right.
There is a need for a selectable one-way clutch that may suppress occurrence of erroneous engagement due to a strut being draw into a notch at the time of ratchet.